The present invention relates to reinforcing bar supports and, more particularly, to support structures capable of supporting reinforcing bars of the type used in continuously reinforced concrete pavement highways.
A continuous reinforcement technique of highway construction has been developed in which the highway lanes are poured with both transverse and longitudinally extending reinforcing bars imbedded in the concrete. The transverse reinforcing bars will generally extend across the entire width of the highway lane. The longitudinally extending reinforcing bars which extend along the highway lane are staggered in their relative positions such that there is no point along the pavement at which all of the bars imbedded therein will end. There are, therefore, no transverse joints to be sealed across the highway lanes, and motorists will experience a smoother ride.
It is necessary to position the reinforcing bars along the sub-base prior to pouring the concrete. Both longitudinal and transverse reinforcing bars must be held during the pouring process so that they will be positioned in the final poured pavement slab according to design specifications. A support structure for the reinforcing bars is therefore required which will be imbedded in the concrete slab. The support structure must hold both longitudinal and transverse bars firmly and, further, must be relatively inexpensive.
One commonly used arrangement for supporting the reinforcing bars in the desired positions during the pouring operation has been to weld a plurality of U-shaped clips at the desired positions along the length of each transverse reinforcing bar. The clips are provided to hold longitudinally extending bars which are laid across the tops of the transverse reinforcing bars. Each transverse reinforcing bar has two or more triangularly shaped metal bases welded to it for holding the resulting grid of reinforcing bars at the desired height. Since each support includes a transverse reinforcing bar, it is apparent that such supports will be relatively expensive. Furthermore, since the vertical positioning of the reinforcing bars, the diameters of the bars, and the spacing between longitudinal bars will vary, depending upon construction specifications, such support arrangements will necessarily be made to order and surplus supports will necessarily be scrapped.
A number of supports for concrete reinforcing rods have been designed in the past, although many, such as those shown in U.S. Pat. No. 3,132,448, issued May 12, 1964, to Phillips et al, and U.S. Pat. No. 2,273,197, issued Feb. 17, 1942, to Hillberg, are capable of supporting only reinforcing rods extending in one direction. It is desirable where both longitudinal and transverse reinforcing rods or bars are to be utilized that the bar support should be capable of supporting transversely oriented bars at their points of intersection.
Other bar supports, such as that shown in U.S. Pat. No. 1,476,939, issued Dec. 11, 1923, to White, have been used which are capable of supporting two reinforcing bars at their point of intersection but which supports cannot be easily interconnected with other similar bar supports. If a plurality of such individual bar supports were to be used, it would be necessary to check frequently the spacing between each adjacent longitudinally extending reinforcing bars. A much more desirable configuration would provide for interconnection of supports across the entire width of the lane so that the longitudinally extending reinforcing bars would necessarily be positioned the desired distance apart.
U.S. Pat. No. 2,439,428, issued Apr. 13, 1948, to Hillberg, shows a bar support structure in which bar supports are interconnected so that their relative spacing is held in fixed relation. This support arrangement is relatively complex in shape. Further, the supports are interconnected in both directions such that the transversely extending reinforcing bars are positioned with respect to each other, as well as the longitudinally extending reinforcing bars. This grid of supports would be relatively difficult to transport and impractical for support in a continuously reinforced construction application.
Accordingly, there is a need for a simple, inexpensive, reinforcing bar support arrangement which will accurately locate the longitudinally extending reinforcing bars with respect to each other and which may be simply and economically produced and transported to the construction site.